Evaluation of plant commercial feed additives for equine cyathostomin control

The increasing emergence of anthelmintic-resistant parasitic isolates prompts us to reassess the management of intestinal strongylosis in horses. Additionally, societal demand is shifting toward reducing the use of chemical treatments, aligning with environmentally-friendly practices and the exploration of natural alternatives. In this context, we provide an initial view of the antiparasitic activity and the effect on immune circulating blood cells of three commercialized plant-based feed additives in ponies. Three treatments, based either on mugwort (Artemisia vulgaris), echinacea (Echinacea purpurea) or curcumin (Curcuma longa) were administrated to 18 (six per treatment) Welsh female ponies naturally infected with cyathostomins to mimic their practical use in farming conditions. Another group of six untreated ponies was used as a control. Fecal egg count (FEC), the larval development percentage and the number of red blood cells, lymphocytes, monocytes, neutrophils, eosinophils and basophils were measured the first and the last day of each treatment, and compared with those characterizing the control group. None of the three treatments showed a significant effect on the studied parameters. Moreover, the efficacy of treatments, measured from the FEC reduction compared to the control group, was weak (≤ 38.6 %). Therefore, these results do not support the practical use of these additives in equine farming, even if the determination of Cohen's d values associated with the three treatments revealed some incidences on FEC and blood immune cell counts, as well as on larval development for mugwort.